The present invention relates to anesthesia machines, and more particularly, to an anesthesia respiratory system that provides a modular form of connector to the patient breathing circuit used to administer an anesthetic to a patient undergoing surgery.
In general, anesthesia systems are utilized in operating rooms and comprise various equipment necessary to anesthetize the patient, support or control respiration, and maintain the patient in that state until the operation is completed and it is possible to terminate the introduction of the anesthetic agent.
Such systems comprise various pressure regulators, flow control devices, gas mixing devices and vaporizers to vaporize a volatile liquid anesthetic into life support gases and to introduce these anesthetic laden gases (fresh gas) to the patient via the respiratory system. The respiratory system provides manual and automatic means to control or support the patients breathing of the fresh gas mixture. The patient is connected to the system by means of a face mask or other device and which interfaces with the respiratory system via a patient breathing circuit that may typically have an inspiratory limb tube through which the gases are introduced into the patient and an expiratory limb tube that conveys the exhaled gases from the patient.
In such systems, the patient breathing circuit conveys the fresh gas from the respiratory system to the patient where the face mask or endotracheal tube connects that patient breathing circuit to the patient. One difficulty, however, with anesthesia machines is the concern that various different types of patient breathing circuits are used for differing reasons by clinicians and therefore the anesthesia machine must be able to operate easily and be adaptable to the various patient breathing circuits. Examples of commonly used patient breathing circuits include the circle type, the open/non-rebreathing circuit and the Bain or Mapleson D circuits. Each are well known circuits commercially available and are used for particular circumstances. Changing from one breathing circuit to another is cumbersome involving a number of different attachments for mounting, fresh gas, sensors, ventilator, etc. depending on the particular anesthesia machine.
Accordingly, the anesthesia machine also handles the various monitoring functions, supplies of gas and the like differently depending on the patient breathing circuit being used. One means of dealing with the differing patient breathing circuits is to utilize a modular form of connector to the anesthesia machine where the respiratory system is standard but has a plurality of interchangeable breathing circuit modules that can be easily inserted for the particular patient breathing circuit being used.
Therefore, if the clinician is utilizing the standard circle patient breathing circuit, that particular breathing circuit module is inserted into the anesthesia machine and provides all the necessary connections to the respiratory system and to the circle patient breathing circuit. Similarly, a separate breathing circuit module is insertable into the machine for other patient breathing circuits, as previously indicated.
As noted, each patient breathing circuit poses differing conditions to the anesthesia machine, that is, a differing fresh gas flow, differing positions and functions of flow sensors and the like and therefore, if the modular approach is used with the anesthesia machine, it is important for the basic central processor unit (CPU) in the anesthesia machine to be able to know which module or patient breathing circuit is being employed so that the processor can determine the correct flow sensor algorithm to activate for volume monitoring or what flows of fresh gas are appropriate for the patient breathing circuit in use and also alert the user as to the module in use
The anesthesia system of the present invention therefore corrects the aforementioned difficulties by providing an easily changeable modular respiratory system that identifies the particular breathing circuit module that is installed in the machine and therefore alerts the central processing unit of the anesthesia machine, and hence the user, as to the identity of the patient breathing circuit so that the correct flows are sensed and the correct flow of fresh gas and the like are provided to the patient.